title: Gonad-gonadotrope interactions: plasma gonadotrophin levels and tumour induction in long-term castrated rats.
abstract: The patterns of gonadotrophin secretion in intact controls and in male and female rats castrated for up to 36 months were established utilizing specific radioimmunoassay methods. Plasma LH increased 14-16 fold and FSH rose 4-8 fold in rats of either sex in the first 30 day interval showed an additional 76% increase of LH in both sexes and increases in FSH of 32 and 61% in males and females, respectively. These levels were maintained for an additional 34 months. The number of hypophyseal gonadotrophin containing cells, studied by immunohistochemical localization techniques, increased following gonad removal in a pattern similar to that for the circulating hormones. Development of gonadotrophin secreting concentrations which suggests that the gonadotropes are uniquely resistant to tumourogenesis unlike mammotropes, thyrotropes, and corticotropes.
mesh_terms: D000818:Animals; D002369:Castration; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood*; D007986:Luteinizing Hormone / Q000097:blood*; D008297:Male; D009374:Neoplasms, Experimental / Q000209:etiology / Q000378:metabolism; D010053:Ovary / Q000502:physiology; D010903:Pituitary Gland, Anterior / Q000166:cytology / Q000378:metabolism* / Q000502:physiology; D010911:Pituitary Neoplasms / Q000209:etiology* / Q000378:metabolism; D011863:Radioimmunoassay; D051381:Rats; D013737:Testis / Q000502:physiology; D013997:Time Factors
chemical_list: D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone